Polio

What is Polio?

Polio is a contagious viral infection caused by the polio virus. The most severe form of the disease includes paralysis and even death but this is uncommon. The virus usually spreads via the feco-oral route. There are three varieties of paralytic polio namely spinal, bulbar and bulbospinal depending upon the site of involvement of the central nervous system.

There is no cure available for polio apart from symptomatic measures like bed rest, healthy diet, painkillers and adequate exercise to gain some of the lost muscle function. Polio has been eradicated from many countries due to childhood immunization programs, however, sporadic cases of polio still occurs in some developing countries.

Polio Symptoms

Non-Paralytic and Paralytic Polio

About 95% of people infected with polio will not suffer from any paralysis but instead experience mild flu-like symptoms such as :

Fever.

Sore throat.

Weakness.

Vomiting.

Stiffness in the neck or back.

Muscle spasms or muscle pain.

Patients also tend to develop meningitis. This type of non-paralytic form of polio lasts for 10 days. Only 1% of polio patients suffer from paralytic symptoms. Initially the symptoms mimic those of the non-paralytic variety but with progression of time, usually within one week, specific symptoms of paralytic polio appear. These paralytic symptoms include :

Gradually progressing muscle or joint weakness with pain.

Generalized weakness.

The affected muscles gradually become floppy, atrophied and paralyzed although sensation remains intact.

Cases of paralytic polio may lead to temporary or permanent paralysis and subsequent deformity of the hip, ankles and feet. Although physical therapy and surgery may improve the condition, in many developing countries children suffer from life long disability because of poor health services.

Causes of Polio

Polio is caused by infection with the poliomyelitis virus. It is a highly contagious virus which spreads from person to person through the intake of food or water that is contaminated with fecal particles from an in infected person. Polio infection peaks during summer and autumn.

Symptoms of polio appear within 6 to 20 days and it is most infectious between 7 and 10 before or after the appearance of the symptoms. However, spread of infection may occur for as long as the patient continues to shed the virus via saliva or feces.

The polio virus enters the body via the oral route and infects the intestinal and pharyngeal cells. After replication the virus reaches the blood stream and enters different organs like the tonsils, muscles, meninges and lymph nodes. In few cases the virus destroys the nerve cells of the central nervous system like spinal cord leading to paralysis.

Types of Polio

Polio is broadly classified as non paralytic (most common) and paralytic varieties (uncommon). The latter is again divided into three subtypes depending upon the site of involvement :

Spinal (most common)

Bulbar

Bulbospinal

Risk factors

No vaccination against polio.

Poor immunity.

Tonsillectomy.

Pregnancy.

Injury to muscles by injection during outbreak.

Visiting areas with recent outbreak of polio.

Treatment of Polio

There is no cure for polio. While patients can make a full recovery especially from the non-paralytic type, the symptoms of paralytic polio may be permanent. Polio is easily preventable by a vaccination, however, immunization programs may not always be the same in every country. The treatment options for polio patients are largely supportive measures such as :